Synergistic compositions containing bis (trichloromethyl) sulfone and their use

ABSTRACT

The present invention relates to certain processes and compositions useful for inhibiting the growth of slime in water and, in particular, water used for industrial purposes; for example, in the manufacture of pulp paper, in the manufacture of paper, in cooling water systems and in effluent water treatment. The novel processes and compositions of the present invention are processes or mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi, and algae, which produce slime in aqueous systems of bodies which are objectionable from either an operational or aesthetic point of view. Specifically, the invention is directed to the use of compositions comprising a combination of a mixture of 75% of 5chloro-2-methyl-4-isothiazolin-3-one calcium chloride and 25% 2methyl-4-isothiazolin-3-one calcium chloride and Bis(trichloromethyl)sulfone.

United a Shema et al.

SYNERGISTIC COMPOSITIONS CONTAINING BIS (TRICHLOROMETHYL) SULFONE ANDTHEIR USE [73] Assignee: Betz Laboratories Inc., Trevose, Pa.

[22] Filed: Mar. 3, 1975 [21] Appl. No.: 554,367

[52] U.S. Cl. 162/161; 106/15 AF; 162/160; 210/64; 252/106; 252/180;424/270 [51] Int. Cl. D21D 3/00; D21H 5/22; A01N 9/12;

[ 51 Dec. 30, 1975 Primary Examiner-Mayer Weinblatt AssistantExaminerEdith R. Buffalow Attorney, Agent, or FirmAlexander D. Ricci[57] ABSTRACT The present invention relates to certain processes andcompositions useful for inhibiting the growth of slime in water and, inparticular, water used for industrial purposes; for example, in themanufacture of pulp paper, in the manufacture of paper, in cooling watersystems and in effluent water treatment. The novel processes andcompositions of the present invention are processes or mixtures whichshow unexpected synergistic activity against microorganisms, includingbacteria, fungi, and algae, which produce slime in aqueous systems ofbodies which are objectionable from either an operational or aestheticpoint of view. Specifically, the invention is directed to the use ofcompositions comprising a combination of a mixture of 75% of5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride and 25%2-methyl-4-isothiazolin-3-one calcium chloride andBis(trichloromethyl)sulfone'l 8 Claims, No Drawings SYNERGISTICCOMPOSITIONS CONTAINING BIS (TRICI-ILOROMETHYL) SULFONE AND THEIR USEBACKGROUND OF THE INVENTION The formation of slime by microorganisms isa problem which attends many systems. For example, lagoons, lakes,ponds, pools, and such systems as cooling water systems and pulp andpaper mill systems all possess conditions which are conductive to thegrowth and reproduction of slime-forming microorganisms. In bothonce-through and recirculating cooling systems, for example, whichemploy large quantities of water as a cooling medium, the formation ofslime by microorganisms is an extensive and constant problem.

Airborne organisms are readily entrained in the water from coolingtowers and find this warm medium an ideal environment for growth andmultiplication. Aerobic and heliotropic organisms flourish on the towerproper while other organisms colonize and grow in such areas as thetower sump and the piping and passages of the cooling system. Such slimeserves to deteriorate the tower structure in the case of wooden towers.In addition, the deposition of slime on metal surfaces promotescorrosion. Furthermore, slime carried through the cooling system plugsand fouls lines, valves, strainers, etc. and deposits on heat exchangesurfaces. In the latter case, the impedance of heat transfer can greatlyreduce the efficiency of the cooling system.

In pulp and paper mill systems, slime formed by microorganisms is alsofrequently and, in fact, commonly encountered. Fouling or plugging byslime also occurs in the case of pulp and paper mill systems. Of greatersignificance, the slime becomes entrained in the paper produced to causebreakouts on the paper machines with consequent work stoppages and theloss of production time or unsightly blemishes in the final productwhich result in rejects and wasted output. The previously discussedproblems have resulted in the extensive utilization of biocides incooling water and pulp and paper mill systems. Materials which haveenjoyed widespread use in such applications include chlorine,organo-mercurials, chlorinated phenols, organo-bromines, and variousorgano-sulfur compounds. All of these compounds are generally useful forthis purpose but each is attended by a variety of impediments. Forexample, chlorination is limited both by its specific toxicity forslime-forming organisms at economic levels and by the ability ofchlorine to react which results in th expenditure of the chlorine beforeits full biocidal function may be achieved. Other biocides are attendedby odor problems and hazards in respect to storage, use or handlingwhich limit their utility. To date, no one compound or type of compoundhas achieved a clearly established predominance in respect to theapplications discussed. Likewise, lagoons, ponds, lakes, and even pools,either used for pleasure purposes or used for industrial purposes forthe disposal and storage of industrial wastes, become, during the warmweather, beseiged by slime due to microorganism growth and reproduction.In the case of the recreational areas, the problem of infection, etc. isobvious. In the case of industrial storage or disposal of industrialmaterials, the microorganisms cause additional problems which must beeliminated prior to the materials use or the waste is treated fordisposal.

Naturally, economy is a major consideration in respect to all of thesebiocides. Such economic considerations attach to both the cost of thebiocide and the expense of its application. The cost performance indexof any biocide is derived from the basic cost of the material, itseffectiveness per unit of weight, the duration of its biocidal orbiostatic effect in the system treated, and the ease and frequency ofits addition to the system treated. To date, none of the commerciallyavailable biocides have exhibited a prolonged biocidal effect. Instead,their effectiveness is rapidly reduced as the result of exposure tophysical conditions such as temperature, association with ingredientscontained by the system toward which they exhibit an affinity orsubstantivity, etc., with a resultant restriction or elimination oftheir biocidal effectiveness.

As a consequence, the use of such biocides involves their continuous orfrequent addition to systems to be treated and their addition to aplurality of points or zones in the systems to be treated. Accordingly,the cost of the biocide and the labor cost of such means of applying itare considerable. In other instances, the difficulty of access to thezone in which slime formation is experienced precludes the effective useof a biocide. For example, in a particular system there is no access toan area at which slime formation occurs and it may only be applied at apoint which is upstream in the flow system. However, the physical orchemical conditions, e.g., chemical reactivity, thermal degradation,etc. which exist between the point at which the biocide may be added tothe system and the point at which its biocidal effect is desired renderthe effective use of a biocide impossible.

Similarly, in a system experiencing relatively slow flow, such as apaper mill, if a biocide is added at the beginning of the system, itsbiocidal effect may be completely dissipated before it has reached allof the points at which this effect is desired or required. As aconsequence, the biocide must be added at a plurality of points, andeven then a graduated biocidal effect will be experienced between onepoint of addition to the system and the next point downstream at whichthe biocides may be added. In addition to the increased cost ofutilizing and maintaining plural feed points, gross in economies inrespect to the cost of the biocide are experienced. Specifically, ateach point of addition, an excess of the biocide is added to the systemin order to compensate for that portion of the biocide which will beexpended in reacting with other constituents present in the system orexperience physical changes which impair its biocidal activity.

It is an object of the present invention to provide methods andcompensations for controlling slimeforming microorganisms in aqueoussystems such as cooling water systems and pulp and paper mill systems,and for controlling slime formation or microorganism populations inaqueous bodies in general. Moreover, another object of the invention isthe provision of methods and compositions for controlling slime-formingmicroorganisms in any aqueous system which is conductive to the growthand reproduction of microorganisms and, in particular, cooling water andpaper and pulp mill systems which employ a combination of a mixture ofof 5-chloro-2-methyl-4-isothiazolin- 3-one calcium chloride and 25%2-methyl-4-isothiazolin-3-one calcium chloride and Bis (trichloromethyl)sulfone.

In practice of the invention, the combination is added to the particularsystem being treated; for example, cooling water systems, paper and pulpmill systems, pools, ponds, lagoons, lakes, etc. in a quantity adequateto control the slime-forming microorganisms which are contained by, orwhich may become entrained in, the system which is treated. It has beenfound that such compositions and methods control the growth andoccurrence of such microorganisms as may populate these particularsystems.

A particular mixture of 5-chloro-2-methyl-4-isothiazolin-3-one calciumchloride and 2-methyl-4-isothiazolin-B-one calcium chloride is availablecommercially as Rohm and Haas RH-886. The individual com ponentsconstituting the mixture are disclosed in German Pat. No. 2,216,108,Nov. 23, 1972 and in Dutch Patent Application 7205 866, laid openNovember 14, 1972. Bis (trichloromethyl) sulfone is available asStauffer N-l386.

As earlier stated, the inventive compositions are comprised of thelatter compounds, either compound being present in such a quantity as toimpart a synergistic behavior to the composition as a whole, the weightratio of the Rohm and Haas RI-I-886 to the Stauffer N-1386 ranging fromabout 95:5 to about 5:95. When these two ingredients are mixed, theresulting mixtures QA l is synergism, 1 is antagonism and =1 isadditivity Qa Q where,

SYNERGISTIC COMBINATION Compound A: a mixture of 75% of5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride and 25%2-methyl-4-isothiazolin-3-one calcium chloride Compound B: Bis(trichloromethyl) sulfone (Stauffer TABLE I TEST ORGANISM AEROBACTERAEROGENES Weight ratio Quantities Producing End Points (ppm) Q Q QA QBof A to B Q, Q Mixture Q. Q5 Q0 Q" possess a high degree of slimicidalactivity of the individual ingredients comprising the mixture.Accordingly, it is therefore possible to produce a more effectiveslime-control agent than has previously been available. Because of theenhanced activity of the mixture, the total quantity of the biociderequired for an effective treatment may be reduced. In addition, thehigh degree of biocidal effectiveness which is provided by each of theingredients may be exploited without use of the higher concentrations ofeach.

To demonstrate the synergism which is provided by the inventivecombinations of compounds, the data as set forth in the Table below wasdeveloped.

EXAMPLE 1 Synergism was demonstrated by adding Compound A and Compound Bin varying ratios and over a range of concentrations to liquid nutrientagar medium (Tryptone Glucose Extract Agar) at approximately 50C. Afterthe medium had solidified in Petri plates, it was inoculated with abacterial suspension. Following two days incubation, the lowestconcentration of each ratio which prevented growth on the agar mediumwas taken as the end point. End points for the various mixtures werethen compared with end points for the pure active ingredients workingalone in concomitantly prepared agar medium plates. Synergism wasdetermined by the method described by F. C. Kull, P. C. Eisman, H. D.Sylwestrowicz and R. L. Mayer, APPLIED MICROBI- OLOGY, 9, 538-41,(1946), and the relationships,

The mode of establishing the synergistic behavior of the compositions ofthe present invention is a widely used and an industrially acceptableprocedure. Although it is believed that the above is sufficient inexplaining the procedure, for a further description thereof referencecan be made to U.S. Pat. No. 3,231,509 and its file history where dataof this nature was considered to be acceptable. Moreover, the article byKull et al published in APPLIED MICROBIOL- OGY, 9, 538-54l, will furnishadditional information in this regard.

For the testing to ascertain synergistic behavior, Aerobacter aerogeneswas favored since this microorganism is found to exist and found to bemost troublesome in pulp and paper producing processes, as well as incooling towers. Moreover, this microorganism is difficult to controland/or kill and accordingly its existence does give rise to troublesomeslime. In view of the foregoing, it can then be appreciated that sinceAerobactor aerogenes is prevalent in most slime-affected systems andsince this micro-organism is difficult to control or kill, that oncecontrol of this microorganism is maintained, then for all practicalpurposes the total microorganism population with its different types isconsidered controlled.

When the inventive compositions are employed in the treatment of coolingor paper mill water, they are preferably utilized in the form ofrelatively dilute solutions or dispersions. For example, a preferredsolution comprises between 5% to by weight of the synergisticcombination in admixture with various solvents and solubilizing agents.

Surfactants such as the alkylaryl polyether alcohols, polyetheralcohols, alkyl benzene sulfonates and sulfates, and the like, may alsobe employed to enhance the dispersibility and stability of theseformations. The foregoing solutions of the biocidal compositions areutilized in order to insure the rapid and uniform dispersibility of thebiocides within the industrial water which is treated. It has been foundthat either aqueous or non-aqueous solvents are generally suitable inthe preparation of compositions of the invention. For example, organicsolvents such as methyl cellosolve and aliphatic and aromatichydrocarbons, e.g., kerosene, can be used quite successfully. Based uponthe synergism study as outlined above, it was ascertained that in thetreatment of paper mill and cooling water, effective biocidal action isobtained when the concentration or treatment level of the combination oradmixture of biocides is between 0.5 parts per million to 1000 parts permillion, and preferably between 1 and 100 parts per million, based uponthe total content of the system treated, such as the total quantity ofcooling water or paper mill water.

The compositions may also be utilized for the preservation of slurriesand emulsions containing carbohydrates, proteins, fats, oils, etc.Dosage levels for the purpose range in the vicinity of 0.01% to 5%.

The compositions of the invention which can be prepared by merelycombining the respective ingredients and mixing thoroughly at standardconditions may be fed continuously to the treated system, e.g., by meansof a metered pump, or may be fed periodically at intervals calculated tocontrol the growth of slime-forming organisms in the systems. Naturally,in the treatment of cooling water the feeding of the inventivecompositions must be designed to compensate for blow-down in thosesystems which employ that expedient.

As would be expected, the inventive composition may be added to thecooling water or paper and pulp mill systems at any convenient point.Naturally, in once-through or non-circulating systems, the compositionmust be added upstream from the point or points at which microorganismcontrol is desired. In circulating systems or pulp and paper systems,the compositions may be added at any point provided that the time lapseand the conditions experienced between point of addition and the pointat which the effect of the composition is experienced are not so drasticas to result in the neutralization of the effect of the composition.

SLIME CONTROL EFFECTIVENESS The inventive methods and materials weretested with respect to their performance in the control of slimeformation in industrial systems. In this test an industrialrecirculating water was obtained from a system which was currentlyexperiencing problems in respect to the formation of slime bymicroorganisms. Such tests do not demonstrate the efficiency of thebiocide employed with respect to specific species of microorganisms, butinstead supply a practical demonstration of the efficacy of the biocidetested in relation to those communities of microorganisms which haveevidenced their ability to form slime in actual industrial systems.

In testing of recirculating water samples, a substrate evaluation wasemployed. In such testing, indentical portions of water samples aretreated with varying concentrations of biocide and two portions are leftuntreated to serve as controls. The control portions are plated fortotal count at the beginning of biocide treatment and all portions areplated for total count at some suitable time period(s) after beginningbiocide treatment. Using the counts obtained from the platings, thepercentage kill (based on the initial control count) may be calculated.In the following example, the water sample was taken from a coolingtower located in eastern Pennsylvania.

For the purposes of comparison, a composition of this invention wasevaluated with two recognized commercial biocides.

EFFICACY RELATIVE TO FUNGI In order to ascertain whether in fact theinventive compositions were effective in controlling fungi, evaluationswere made following the procedure described by Shema et al., JOURNAL FORTHE TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUS- TRY, 36, 20A-3OA,1953. The described procedure generally entails incorporating thebiocide under test in a nutrient substrate such as agar, malt, etc. andpouring the resulting medium in a Petri dish and allowing the medium tosolidify. A button of fungus inoculum is placed on the surface of thesolified medium and the medium is incubated for a period of 14 days.After the period, the diameter of the colony is measured and comparedwith the diameter of the button of inoculum originally placed upon thesurface. If there is no increase in the diameter, the growth of thefungus is considered to be completely inhibited and the treatment levelwhich effectuates this is considered the inhibitory concentration.

The fungi species utilized as the test microorganisms to evaluate theefficacy of the present compositions were Penicillium expansum andAspergillus niger. The

study revealed that the above 10% active composition of this inventioninhibited the growth of Pencillium expansum at a treatment level of 400ppm and 600 ppm completely inhibited the growth of Aspergillus niger.

BACTERICIDAL EFFECTIVENESS achieve complete inhibition of the growth ofthe test organism. The biocide RX-38 is available commercially from BetzLaboratories, Inc. and contains as active ingredients about 5% methylenebisthiocyanate and about 17% hexachloro dimethyl sulfone by weight,

Inhibition Biocide Materials quantity (ppm) 1. Compound A (5%) '40Compound B (5%) l5 inert (90%) 2. Betz Slime-Trol RX-38 (100%) 30Accordingly, since the waters of pulp and paper mills 20 and the waterof cooling water systems generally predominately contain bacteria suchas Aerobacter aerogenes and some fungi such as Penicillium expansum andAspergillus niger, it is apparent from the foregoing evaluations andstudies that the inventive composition will effectuate the claimedobjective of controlling microorganisms of aqueous systems.

It should be noted that while the preponderance of evidence has beenderived from the treatment of samples taken from paper and pulp millaqueous systems,

the compositions and methods of the present invention are broadlyapplicable to the treatment of aesthetic, waters as well as industrialwaters such as cooling waters which are plagued by deposits formed byslimeforming organisms, or by the very presence of such organisms.

Having thus described the invention, what is claimed 11. A compositionfor the control of the microorganism Aerobacter aerogenes in aqueoussystems comprising a mixture of of5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride and 25%2-methyl-4-isothiazolin-3-one calcium chloride with Bis(trichloromethyl) sulfone wherein the weight ratio of the chloridemixture to the sulfone ranges from about :5 to about 5:95 respectively.

2. The composition of claim Il where said ratio is about 50:50.

3. A method for controlling the growth of the microorganism Aerobacteraerogenes in an aqueous system which comprises adding to said system agrowth inhibiting amount of a composition comprised of a mixture of 75%OF 5-chloro-2-methyl-4-isothiazolin-3-one calcium chloride and 25%2-methyl-4-isothiazolin-3-one calcium chloride with Bis(trichloromethyl) sulfone wherein the weight ratio of the chloridemixture to the sulfone ranges from about 95:5 to about 5:95respectively.

4. The method of claim 3 wherein said ratio is about 50:50.

5. The method of claim 3 wherein said composition is added to saidsystem in an amount of from 0.1 to about 1000 parts per weight of saidcomposition per million parts by weight of said aqueous system.

6. The method of claim 5 where said composition amount is from about 1to about parts per million of said aqueous system.

7. The method of claim 5 wherein the aqueous system is that of a coolingwater system.

8. The method of claim 5 wherein the aqueous system is that of a pulpand paper mill system.

1. A COMPOSITION FOR THE CONTROL OF THE MICROORGANISM AEROBACTERAEROGENES IN AQUEOUS SYSTEMS COMPRISING A MIXTURE OF 75% OF5-CHLORO-2-METHYL-4-ISOTHIAZOLIN-3-ONE CALCIUM CHLORIDE AND 25%2-METHYL-4-ISOTHIAZOLIN-3-ONE CALCIUM CHLORIDE WITH BIS(TRICHLOROMETHYL) SULFONE WHEREIN THE WEIGHT RATIO OF THE CHLORIDEMIXTURE TO THE SULFONE RANGES FROM ABOUT 95:5 TO ABOUT 5:95RESPECTIVELY.
 2. The composition of claim 1 where said ratio is about50:50.
 3. A method for controlling the growth of the microorganismAerobacter aerogenes in an aqueous system which comprises adding to saidsystem a growth inhibiting amount of a composition comprised of amixture of 75% OF 5-chloro-2-methyl-4-isothiazolin-3-one calciumchloride and 25% 2-methyl-4-isothiazolin-3-one calcium chloride with Bis(trichloRomethyl) sulfone wherein the weight ratio of the chloridemixture to the sulfone ranges from about 95:5 to about 5:95respectively.
 4. The method of claim 3 wherein said ratio is about50:50.
 5. The method of claim 3 wherein said composition is added tosaid system in an amount of from 0.1 to about 1000 parts per weight ofsaid composition per million parts by weight of said aqueous system. 6.The method of claim 5 where said composition amount is from about 1 toabout 100 parts per million of said aqueous system.
 7. The method ofclaim 5 wherein the aqueous system is that of a cooling water system. 8.The method of claim 5 wherein the aqueous system is that of a pulp andpaper mill system.